Refrigerating apparatus



May-5112fi931. o. M. SUMMERS REFRIGERATING APPARATUS Filed Dec.

Patented May 12, 1931 UNITED STATES PATENT OFFICE OTTO M. SUMMERS, OF DAYTON, OHIO, ASSIGNOR TO FRIGIDAIRE COIR'IE'OIRA'JJIOIN,v OF

DAYTON, OHIO, A CORPORATION OF DELAWARE REFRIGERATING APPARATUS Application filed December 31, 1929. Serial No. 417,703.-

This invention relates to refrigerating apparatus and has particular reference to the evaporator or the low pressure side of refr gerating apparatus.

One of the objects ofthis invention is to prevent an accumulation of an excessive amount of liquid other than refrigerant 1n the evaporator or on the low pressure side of a refrigerating system.

Another object of the present inventlon is to utilize the change in pressure, due-t0 the change in temperature, for preventing accumulation of an excessive amount of liquid other than refrigerant in the evaporator of the refrigerating system.

A still further object is to provide means for and a method of returning such liquid only during the latter part of the operating cycles of the refrigerating system.

' Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawing, wherein a preferred form of the present invention is clearly shown.

In the drawings:

Fig. 1 is a view showing in section apreferred form of an evaporator, and showing diagrammmatically the remaining elements of a refrigerating system;

Fig. 2 is a detail view of part of the throttling mechanism of Fig. 1 in the open position; and

Fig. 3 is a top view of Fig. 2.

In Fig. 1 is disclosed diagrammatically a portion of a refrigerating system comprising a compressor 10 for compressing the refrigerant, pi eferably sulphur dioxide, and for forwarding it to the condenser 11 where it is liquefied and collected in the receiver 12. The actuating means for the compressor preferably comprises a motor 13 connected by pulley and belt means 14 to the compressor 10. A supply conduit 15 conducts liquid refrigerant to the evaporator 20, while the conduit 16 conducts gaseous refrigerant from the evaporator to the compressor, and pressure responsive means 17 is preferably connected in the return conduit 16 for controlling the motor 13 to provide alternating operating and idle periods of the compressor accord- 4 outlet valve 24 and an inlet valve 25 supported thereon. The inlet valve 25 for the liquid referigerant enters into agradually restricted passage through a boss 26 on the innerside of the valve plate. A supporting bracket 27 is attached to this boss and supports a float ball 28 and float ball arm 29 operating the needle valve30 for controlling the flow of liquid refrigerant into the evaporator.

The outlet valve 24 communicates through the valve plate to a long outlet tube 31 having an open end 32. Pivoted on the side of this tube is a portion of a throttling mechanism preferably formed of a U-shaped member including a front 33 and the legs 34. These legs 34 are pivoted on the side of the tube at the points 35. Just in front of this pivoted form is an actuating member 36 at .tached to this throttling mechanism and connected to a controlling member 37 preferably in the form of a closed diaphragm. This diaphragm is supported by bracket 38 on the bracket 27. The closed diaphragm is, of course, means responsive to conditions within the evaporator as it will expand when the pressure and likewise the temperature within the evaporator decreases because the exterior pressure is lessened and it will collapse when the pressure and likewise the'temperature within the evaporator increases because the exterior pressure becomes greater than its interior pressure. An interior spring 3-9 prevents complete collapse of the closed diaphragm.

Also connected to the outlet tube 31 is an oil or lubricant conduit 40 acting as a-by-pass for a large portion of the tube 31and especially its throttling mechanism. This tube has an opening at 41 into the tube 31 and. preferably extends towards the rear of the evaporator and curves downward towards the liquid refrigerant at a place just in the front of the float ball 28. The open end of the tube is protected by a baiile 43 to provide a relatively quiet zone below the tube whereby substantially only oil will be present at the mouth of the tube. This bafiie 43 ineludes two upright sides 44 which are bent inwardly to provide top portions 45. Each of the portions 45 are provided with ears 46 which are soldered to a nut 47 which in turn is secured to the tube 42. The narrow sides or ends of the baflie 43 are open as at 48 so that a lubricant level is maintained above the battle the same as in the tank 20.

As disclosed in Fig. 1 the liquid refrigerant generally occupies a level such as that disclosed at the reference numeral 49 in the evaporator. Oil from the crankcase is generally carried along with the refrigerant and forms an oil blanket 50 on top of the liquid refrigerant. If this oil blanket becomes too thick it will interfere with the efliciency of the device. Accordingly it is very desirable to maintain the oil blanket at a certain maximum height. In the device this is determined by the height of the open end 42 of the oil conduit 40.

When the temperature of the evaporator is high the pressure of the refrigerant gas in the closed system will cause the diaphragm 37 to collapse, as disclosed in Fig. 2. When the compressor operating phase begins, the compressor will pump down the evaporator causing a lowering of the temperature and the pressure therein with the result that the diaphragm 37 will expand and by means of the connecting member 36 gradually raise the throttling mechanism until the front member 33 is over the open end of the outlet tube 31.

a The pressure operated means 17 is arrangedto start the motor at a predetermined high pressure and stop the motor at a predetermined low pressure within the evaporator. When the compressor first starts there is, under certain operating conditions, considerable turbulence of the refrigerant oil due to the rapid evaporation of the refrigerant. Accordingly it is not desirable to remove oil from the evaporator during the first part of the compressor operating phase because a cer-- tain amount of liquid refrigerant will be carried with the oil and this liquid refrigerant will cause refrigeration outside of the evaporator. The diaphragm 37 is adjusted to start the throttling operation a short time before the predetermined low pressure is attained and the inlet of the tube 32 will be substantially closed just before the predetermined low pressure is attained. The refrigerant gas having its main opening closed off by the throttling mechanism will seek other means of passing into the tube 31 and this will bedone through the conduit 40. However, as this conduit 40 will be reaching down into the oil, the oil above its level will be drawn up by the pressure of the gas seeking to be drawn into the tube 31 by the suction created by the operation of the compressor 10. Accordingly all the oil above the level of the tube 42 will bedrawn up during the latter portion of the compressor operating phase, when the boiling is less violent, into the outlet tube 31 and will then find its way back to the crankcase of the compressor 10 by gravity. It may be advisable to provide one or more holes 47 in the tube 31 so that the pressure is not too suddenly cut off by the throttling mechanism.

Preferably air is partially exhausted from the diaphragm chamber 37 but it is to be understood that fluids other than air could be used and the pressure thereof varied to suit the proper operating conditions of the system.

Thus it is apparent that I have provided for the return of an excessive amount of oil to the compressor and I have prevented the flow of liquid refrigerant with the returning 1 oil. By withdrawing the oil from the evaporator only at the end of the compressor operating phase at which time the boiling is less violent, a small amount, if any, liquid refrigerant will be withdrawn from the evaporator.

While the form of embodiment of the invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

\Vhat is claimed is as follows 1. A refrigerating system including an evaporator and a refrigerant supply unit for supplying refrigerant together with liquid to said evaporator, means for operating said refrigerant supply unit in cycles, and means to withdraw excess liquid from said evaporator, said means being operative during the latter part only of the operation of the refrigerant supply unit.

2. A refrigerating system including an evaporator and a refrigerant supply unit for supplying refrigerant together with a liquid to said evaporator, means for operating said refrigerant supply unit in cycles, and means to withdraw excess liquid from said evaporator, said means being operative only during the latter part of the operation of the re-' frigerant supply unit, and comprising a mechanism to throttle the outlet for the evaporated refrigerant and a conduit by-passing said mechanism.

3. A refrigerating system including an evaporator and a refrigerant supply unit for supplying liquid refrigerant and a liquid to said evaporator, means for operating said refrigerant supply unit in cycles, and means to withdraw excess liquid from said evaporator, said means being operative only during the latter part of the operation cycle of the refrigerant supply unit and comprising a mechanism to throttle the outlet for the evaporat ios ed refrigerant, a conduit by-passing said mechanism, and a pressure responsive means for 0 crating said mechanism.

4. n refrigerating apparatus wherein is utilized aworking fluid comprising a refrigerant and a li uid separable by gravity, the combination of an evaporator, means for supplying said liquid and liquid refrigerant to and for withdrawing gaseous refrigerant from said evaporator, and means responsive to pressure due to changes in temperature of said evaporator, said last named means cooperating with said vapor withdrawing means during a part only of the operation of the withdrawing means for returning liquid to said withdrawing means.

5. In refrigerating apparatus wherein is utilized a working fluid comprising a refrigerant and a liguid separable by gravity, the combination 0 an evaporator, means for supplying said liquid and liquid refrigerant to and for withdrawing gaseous refrigerant from said evaporator, and means responsive to pressure due to changes in temperature of the evaporator, said last named means coopcrating with said va or withdrawin means for returning liqui to said with rawing means.

6. In a refrigerating apparatus wherein a working fluid comprising a refrigerant and a lubricant separable by gravity is utilized, the combination of an evaporator, means for supplying liquid refrigerant to and for withdrawing gaseous refrigerant from the evaporator, some of said lubricant passing from said means to the evaporator with the refrigerant delivered to the evaporator and some of said lubricant passin from said evaporator to said means with t e gaseous refrigerant,

and means responsive to temperature conditions for causing an increased flow of lubricant from the evaporator to said means.

7. In a refrigerating apparatus wherein a working fluid com rising a refrigerant and a lubricant separa 1e by gravity 1s utilized, the combination of an evaporator, means for supplying liquid refrigerant to and for withdrawing gaseous refrigerant from the evaporator, some of said lubricant passing from said means to the evaporator with the refrigerant delivered to the evaporator and some of said lubricant passing from said evaporator to saidmeans with the gaseous refrigerant, means for maintaining a substantially constant quantity of liquid refrigerant in the evaporator, and means responsive to chan es in pressure due to changes in temperature or causing an increased flow of lubricant from the evaporator to said first mentioned means. 8. In a refrigerating apparatus wherein a working fluid comprising a refrigerant and a lubricant separable by gravity is utilized, the combination of an evaporator, means forsu slying liquid refriggrant to and for wit rawmg gaseous re gerant from the evaporator, some of said lubricant passing from said means to the evaporator with the refrigerant delivered to the evaporator and some of said lubricant passing from said evaporator to said means with the gaseous refrigerant, a conduit for conveying excess lubricant, which accumulates in-the evaporator, to the vapor outlet of the evaporator, a single valve for controlling the flow of lubricant through said conduit, and means responsive to temperature conditions for actuating said valve.

9.,In a refrigerating apparatus wherein a working fluidcomprising a refrigerant and a lubricant separable by gravity is utilized, the combination of an evaporator, means for supplying liquid refrigerant to and for withdrawing gaseous refrigerant from the evaporator, some of said lubricant passing from said means to the evaporator with the refrigerant delivered to the evaporator and some of said lubricant passing from said evaporator to said means with the gaseous refrigerant, a conduit for conveying gaseousrefrigerant and excess lubricant, which accumulates in the evaporator, to the vapor outlet of the evaporator, a single valve for throttling the gaseous refrigerant inlet to said conduit and for increasing the flow of lubricant through the conduit, and means responsive to temperature conditions for actuating said valve.

10. In a refrigerating apparatus wherein a working fluid comprising a refrigerant and a lubricant separable by gravity is utilized,

thecombinationof an evaporator, means for supplying liquid refrigerant to and for withdrawing gaseous refrigerant from the evaporator, some of said lubricant passing from said means to the evaporator with the refrigerant delivered to the evaporator and some of said lubricant passing from said evaporator to said means with the gaseous refrigerant, a conduit for conveying gaseous refrigerant to the vapor outlet of the eve orator, means communicatin with said con uit and extend ing into the In ricant within the evaporator, a single valve for throttling the gaseous refrigerant inlet of said conduit and for causing the flow, of excessive lubricant accumusignature.

QTTO M. SUMMERS. 

